Add script tool to normalize jsonbin sidecar paths in existing NVBench JSON files

[oleksandr-pavlyk]

Problem

Older NVBench jsonbin output can contain sidecar filenames that are not relative to the JSON file location, see #404. This makes post-processing fragile when benchmarks are launched from one working directory but the JSON output is written elsewhere.

Desired Tool

Add a script that rewrites existing NVBench JSON files so that jsonbin sidecar filenames are normalized relative to the JSON file’s directory.
The tool should:

• Read an NVBench JSON file.
• Locate jsonbin sidecar summaries, including sample time and frequency sidecars.
• Resolve existing sidecar files from candidate locations.
• Rewrite filename fields to paths relative to the JSON file directory.
• Preserve all other JSON content.
• Provide a dry-run mode.
• Support either in-place update with backup or writing to a separate output file.

Ambiguity Handling

Some files may be resolvable from multiple locations. The tool should avoid guessing silently. Possible options:

nvbench-normalize-jsonbin result.json --dry-run
nvbench-normalize-jsonbin result.json --in-place
nvbench-normalize-jsonbin result.json --output normalized.json
nvbench-normalize-jsonbin result.json --sidecar-root /path/to/use

If multiple candidates match, the tool should report the ambiguity and require --sidecar-root or another explicit resolution option.

Acceptance Criteria

• Normalized JSON works when moved together with its sidecar directories.
• Missing sidecars are reported clearly.
• Ambiguous sidecar resolution is not silently guessed.
• Existing valid JSON-relative sidecar paths are left unchanged.
• Tests cover current JSON-relative files and older launch-directory-relative files.

Motivation

This complements the jsonbin sidecar path fixes (#405 and change to nvbench-compare in #386) for newly generated output while providing a migration path for previously collected benchmark data.